Purpose
The primary aim was to evaluate whether
anti
-3-[
18
F]FACBC PET combined with conventional MRI correlated better with histomolecular diagnosis (reference standard) than MRI alone in glioma diagnostics. The ability of
anti
-3-[
18
F]FACBC to differentiate between molecular and histopathological entities in gliomas was also evaluated.
Methods
In this prospective study, patients with suspected primary or recurrent gliomas were recruited from two sites in Norway and examined with PET/MRI prior to surgery.
Anti
-3-[
18
F]FACBC uptake (TBR
peak
) was compared to histomolecular features in 36 patients. PET results were then added to clinical MRI readings (performed by two neuroradiologists, blinded for histomolecular results and PET data) to assess the predicted tumor characteristics with and without PET.
Results
Histomolecular analyses revealed two CNS WHO grade 1, nine grade 2, eight grade 3, and 17 grade 4 gliomas. All tumors were visible on MRI FLAIR. The sensitivity of contrast-enhanced MRI and
anti
-3-[
18
F]FACBC PET was 61% (95%CI [45, 77]) and 72% (95%CI [58, 87]), respectively, in the detection of gliomas. Median TBR
peak
was 7.1 (range: 1.4–19.2) for PET positive tumors. All CNS WHO grade 1 pilocytic astrocytomas/gangliogliomas, grade 3 oligodendrogliomas, and grade 4 glioblastomas/astrocytomas were PET positive, while 25% of grade 2–3 astrocytomas and 56% of grade 2–3 oligodendrogliomas were PET positive. Generally, TBR
peak
increased with malignancy grade for diffuse gliomas. A significant difference in PET uptake between CNS WHO grade 2 and 4 gliomas (
p
 < 0.001) and between grade 3 and 4 gliomas (
p
 = 0.002) was observed. Diffuse IDH wildtype gliomas had significantly higher TBR
peak
compared to IDH1/2 mutated gliomas (
p
 < 0.001). Adding
anti
-3-[
18
F]FACBC PET to MRI improved the accuracy of predicted glioma grades, types, and IDH status, and yielded 13.9 and 16.7 percentage point improvement in the overall diagnoses for both readers, respectively.
Conclusion
Anti
-3-[
18
F]FACBC PET demonstrated high uptake in the majority of gliomas, especially in IDH wildtype gliomas, and improved the accuracy of preoperatively predicted glioma diagnoses.
Clinical trial registration
ClinicalTrials.gov ID: NCT04111588, URL:
https://clinicaltrials.gov/study/NCT04111588...

Diagnostic accuracy of anti-3-[18F]-FACBC PET/MRI in gliomas

10.1007/s00259-023-06437-4